PC randomly just switching off

MothballsWallet

My desktop PC's been switching off suddenly over the last few days for a reason I can't determine. I can be watching videos on YouTube or just copying files between the PC and my external hard drive for a few hours and then, suddenly, it just switches off.

I then have to switch everything off at the mains, wait a few minutes, and then switch it all back on again.

I've opened up the PC's case and tried to remove as much dust as I can because, well, it hadn't been cleaned for a while.

When I restarted it recently, I checked the temperatures in the BIOS, which said System 41 degrees C, CPU 56 degrees C.

This is an Athlon64 3200+ based system that I bought in 2004 with 1GB RAM, 200GB hard drive, DVD-ROM & DVD-RW, ATI Radeon graphics, Creative Audigy 2ZS sound card, 2 USB2 & 6 USB1.1 ports using Windows XP Pro with SP3.

Now this problem does sound like what I had with my laptop before I managed to screw up its boot data completely, which hinted at a hardware problem like a hard drive failure.

I'm thinking of getting in touch with the shop I bought it from to see if they could do a once-over on it to check everything out. I'm also going to try and run a full CHKDKSK to see if there are any errors on the hard drive (XP did a shortened one on Saturday, fixed some errors and reported 0 bad sectors).

Any advice welcomed

paddyrg

Also, just try reseating the RAM and any cards - the hot/cold cycle might have wriggled just one tiny connector a wee bit loose. Takes 2 mins so worth a try.

MothballsWallet

I've also tried running a full CHKDSK - steps 1-3 finished, but step 4 (verify file data) only got to about 3% before power off occurred.

I'll try reseating the DIMMs later - even though they look okay you never know.

The local firm I got it from's still in business and, since I don't have any thermal paste, I might see if they do PC servicing as well

I won't tamper with the PSU though, which is why I'd want to contact the PC shop in case it needs a PSU swap-out. Unless there's something I can do to help clean out the PSU without opening its box up (because it's labelled with warnings about only trained service people should open it).

I'm annoyed with myself because when I'd unplugged everything at the back, I forgot to unplug the USB Wifi dongle from the front and managed to bend its USB plug when I was lifting the machine to take it through to my work bench.

WendellG

PSU units are pretty standard and easy to change, there's usually just 4 screws near the fan that holds it in place.

Just make sure you get a replacement with the right connectors (IDE or SATA) and the right wattage. It shouldn't cost more than £20.

It could also be down to the CPU or something on the motherboard, but all you can do is eliminate possibilities.

harleq1962

had a pc like this it turned out to be faulty ram, replaced the power supply and heatsink. just switched off when it felt like, also had some with faulty power supplies that had been used either in a bedroom or an enclosed pc cabinet,

MothballsWallet

WendellG wrote: »

PSU units are pretty standard and easy to change, there's usually just 4 screws near the fan that holds it in place.

Just make sure you get a replacement with the right connectors (IDE or SATA) and the right wattage. It shouldn't cost more than £20.

I think the PSU make and model's visible on one of its labels, so I can try getting a like for like of that.

WendellG wrote: »

It could also be down to the CPU or something on the motherboard, but all you can do is eliminate possibilities.

I hope not - it runs fine for a set amount of time and then goes off.

I've emailed the shop I bought it from to find out what their repair charges are so that, should the worse happen and I can't fix it, I can get them to fix it for me.

MothballsWallet

harleq1962 wrote: »

had a pc like this it turned out to be faulty ram, replaced the power supply and heatsink. just switched off when it felt like, also had some with faulty power supplies that had been used either in a bedroom or an enclosed pc cabinet,

Mine is in a bedroom, next to the outer (south-facing) wall, but it isn't enclosed just sitting on the floor.

Anyone know where I can get a plinth-like stand to put it on so it's not just resting on the floor?

Mr_Toad

As well as cleaning it did you check that all the fans are running?

MothballsWallet

Mr_Toad wrote: »

As well as cleaning it did you check that all the fans are running?

What's the best way to do that?

I ask because I took it through to another room to clean it, the fan noise level sounds like it does in normal operation.

I'm a bit anxious about running it with the case opened (live circuits and my fear of getting an electric shock) - I suppose I could do it with just the keyboard, mouse and monitor plugged in to begin with.

Spankey

You may have about 3 fans in there, processor,psu,graphics card fan, and maybe a case fan.
Just open the side and look at all the fans and see if they spin once you start the pc, in the pasy 9/10 times it has been the memory or the psu for my pc repairs when a shutdown like yours happens.

MothballsWallet

Update for everyone:

Sunday evening I managed 6 1/2 hours runtime without issues before I had to shutdown and go to bed. I was only browsing MSE and checking emails though, so not too much processor usage.

Checked cards and memory - I took them out and reseated them, so they should be connecting okay.

Fans: As Spankey says, I have 3:

CPU: Spinning.
PSU: Spinning.
Graphics (GPU): Doesn't appear to be spinning.

I also had a weird effect on the graphics earlier where the display got garbled, so that's when I shut down and took it into the back room to work on.

Is it possible that the GPU fan is hosed?